PROJECT SUMMARY/ABSTRACT Over 180,000 men will be diagnosed with localized prostate cancer in 2016 and 92% of these men will have localized or regional disease. Fortunately, treatment with curative intent (surgery or radiation with/without hormone therapy) provides long-term cancer-free survival. However, survivors experience urinary, sexual, bowel and hormonal symptoms, general distress, pain, fatigue, and sleep disturbance. For men in an intimate relationship, these symptoms disrupt couple?s relationships and intimacy, and reduce quality of life (QOL) of both patients and their partners who are often their primary caregivers. Symptom effects may have as great or greater impact on their partners? QOL than on patients? own QOL. Management of the negative effects of cancer and its treatment is a significantly under-addressed supportive care need for these men and their intimate partners. Most existing online programs are not couple-focused or use generalized ?one-size fits all? approaches that have fallen short of improving QOL. Existing in-person couple-focused programs are expensive and inconvenient because of the time and travel required. To address these unmet supportive care needs, Dr. Song led an interdisciplinary team to develop and pilot test the usability and feasibility of an evidence-based, couple-focused, tailored mobile health (mHealth) intervention, ?Prostate Cancer Education & Resources for Couples? (PERC). Based on the adapted stress-coping theoretical framework and developed with stakeholder involvement, PERC aims to improve QOL for both patients and partners through enhancing positive appraisals, self-efficacy, social support, and healthy behaviors for symptom management. Using mHealth technologies, PERC provides comprehensive, user-friendly content, and uses tailoring and personalization features designed to increase personal relevance of, and couples? accessibility to PERC modules. We propose to rigorously test the efficacy of PERC using a population-based, geographically and demographically diverse cohort in a randomized controlled trial. The specific aims are: Primary Aim: Assess if patients and partners receiving PERC will report greater improvement in their cancer-related QOL scores than those in the control group (usual care plus the National Cancer Institute (NCI) prostate cancer website) at 4, 8, and 12 months post-baseline. Secondary Aim: Test if patients and partners in PERC will report significantly more positive appraisals and higher levels of coping resources at follow-ups than those in the control group. Exploratory Aim: Determine if patient race and ethnicity, education, type of treatment, or couples? relationship quality moderate the effects of PERC on patient and partner QOL at follow-ups. This study will provide a novel model for self-managing chronic illness symptoms that impact couples? relationships, intimacy, and QOL. It addresses the National Institute of Nursing Research?s (NINR) goal to develop and test new strategies for symptom self-management to help patients and caregivers better manage their illness and improve QOL. It also responds to calls for programs from the Institute of Medicine (IOM) and American Cancer Society (ACS) to address treatment-related effects and improve survivors? QOL.